Various systems are known which monitor a person's heart rate, respiration rate, body temperature, and the like. For ambulatory-type systems, a portable unit may be used to wirelessly transmit the various sensor signals to a base station computer for processing, display, and storage.
For sport, outdoor, and military applications especially, the portable unit must be waterproof and removable from the shirt or garment carrying the sensors in order to wash the shirt or garment. The electrical connections between the sensors and the portable unit must be robust. And yet, no system will be commercially viable if numerous manual labor steps are required increasing manufacturing costs. The portable unit must be small, remain electrically connected to the sensors while in use, and not interfere with the activity being carried out by the user.
Several wearable physiological monitoring systems have been proposed. They typically include one or more sensors (e.g., a respiration sensor, a heart rate sensor, an accelerometer, and the like). Using a transmitter, the sensed data is transmitted to a base/readout unit. Some prior art references disclose a sensor subsystem with a transmitter apparently hard wired to the sensors. See, e.g., U.S. Published Patent Application No. 2005/0240087 and U.S. Pat. No. 6,416,471, incorporated herein by this reference.
Other prior art references disclose a stand alone sensor/transmitter unit carried by the user. See, e.g., U.S. Pat. No. 7,092,846. Such systems cannot sense respiration, heart rate, and the like. The APPLE+NIKE product, now on the market, is similar.
For sports, military, and other applications where the sensor subsystem is integrated into a shirt or other garment, the garment is typically washed between uses. Also, when worn, it is important that nothing interfere with the user's comfort. Some physiological monitoring systems are not comfortable to wear; others are difficult to use. Some require preparation prior to and/or after donning the garment. Some include discrete wires which must be routed and/or connected each time the garment is worn. Some include electrodes which must be secured to the person's body and/or must be used in connection with a conductive gel. Some physiological monitoring garments are simply not aesthetically pleasing. Others interfere with the activities of and duties carried out by the wearer.
Respiration can be sensed in a couple of different ways. See U.S. Pat. Nos. 4,815,473; 5,301,678; 6,047,203 incorporated herein by this reference. One respiration sensing subsystem includes a flexible band with a pair of spaced conductors extending along the band in a flexible configuration. The band is fitted about the person's chest and, as the person inhales and exhales, the distance between the two conductors changes. This change in distance between the two conductors can be sensed to provide respiration data. See U.S. Pat. No. 7,559,902, incorporated herein by this reference.
In non ambulatory, non-athletic uses, such respiration sensing subsystems function adequately. When the applicant began testing such systems on athletes, soldiers, and for use in other ambulatory environment, however, the detected respiration rate of the subject slowly went down to zero even though it was clear that the subjects were still breathing.